Margin status is one of the most clinically consequential findings in a surgical pathology report, and I will explain exactly what it means and what the implications are. When a surgeon removes a tumour, the pathologist receives the entire surgical specimen. The cut surfaces of this specimen, the edges where the surgeon divided the tissue to remove it, are called the surgical margins. The pathologist's job is to assess whether cancer cells are present at or near these cut edges. The margins are described as clear, negative, or free when there is a measurable distance of normal tissue between the nearest cancer cells and the cut edge, meaning the tumour has been completely removed with a surrounding cuff of healthy tissue. The margins are described as positive or involved when cancer cells are actually present at the cut edge itself, meaning that when the surgeon made the cut to remove the tumour, the cut passed through cancerous tissue, leaving cancer cells behind in the patient. Positive margins have direct clinical consequences. In the majority of cancers, a positive margin indicates that residual cancer is likely present in the body at the surgical site, and that either re-excision (another operation to remove more tissue from the involved margin area) or radiotherapy to the tumour bed is usually recommended. The decision between re-excision and radiotherapy depends on the cancer type, the location, the extent of the margin involvement, and the overall treatment plan. In some cases, such as a focal positive margin at one edge of a large breast conservation specimen, a decision may be made to proceed with radiotherapy rather than further surgery. In other situations, such as an involved margin following rectal cancer resection, re-excision or combined treatment may be recommended. When you receive a report stating positive margins, the appropriate response is to return to your surgeon and oncologist with the pathology report and ask specifically: what is the recommended next step in my case, and why? The pathology department at PESIMSR, Kuppam, is available to discuss the technical aspects of the report if the treating team requires clarification.
Related reading: From Biopsy to Diagnosis: A Complete Guide to What Pathologists Do and Why It Matters for Your Treatment
Histopathology and Cancer Diagnosis: How Tissue Analysis Guides Treatment Decisions
Why Quality Management Is the Foundation of Safe and Effective Healthcare
Get to Know Your Doctor: Dr Anikode Subramanian Ramaswamy, Expert Pathologist, Researcher, and Laboratory Quality Specialist
Written by Dr. Anikode Subramanian Ramaswamy, MBBS, MD (Pathology), Professor and Head, Department of Pathology, PESIMSR, Kuppam, Andhra Pradesh 517425. ISO 15189 Assessor. 75 peer-reviewed publications. Phone: +91 9493726494.
